Process control station safety communication method and system and decentralized control system

The invention discloses a process control station safety communication method comprising the following steps: responding to a normal mode, and receiving and analyzing a data packet sent by a monitoring background; discarding the data packet in response to the fact that the data packet does not conform to the preset access control rule; in response to the fact that the data packet conforms to a preset access control rule and the read-write permission in the data packet is enough, writing the read-write request into an internal output variable area; and in response to the fact that the data packet conforms to the preset access control rule and the read-write permission in the data packet is insufficient, refusing to execute the read-write request, and feeding back an error to the monitoringbackground. Meanwhile, the invention discloses a process control station safety communication system and a decentralized control system. According to the invention, the safety communication of the process control station is r